Steel alloy



' Patented Sept. 1931 STATES PATENT orrlcs DAVID FRANKLIN YOUNGBLOOD, OF SAN ANTONIO, TEXAS STEEL ALLOY No Drawing.

This invention relatesto hard steel alloys and aims to provide a special, tool-reslstant, heat-resistant and rust-resistant steel, es ecially adapted for jails, vaults and the li e,-

5'to prevent breaks from jails or theft from vaults, by the use of ordinary tools.

Heretof0re, it has been customary to make tion. The usual bars of this characterconsist of approximately hard steel and 80% soft steel. However, lon experience has taught that if such material is made sufliciently ductile to withstand blows and strains, it will not resist saws, files, and drills. Neither will it resist heat and rust. This inven- ..tion aims to'produce a special high-grade, alloy steel that possesses all of these necessary qualities in a solid form, without lamination. One example of the improved alloy steel that has the foregoing qualities, includes the following materials Percent Carbon L..' I t0 Manganese 6.50 to 7.50

Silicon 0.60 to 0.70 Chromium .1.00 to 1.50

a- Molybdenum 0.25 to 0.40

The carbon, manganese, silicon, chromium and molybdenum all contribute to hardness andtoughness without making the metal too brittle and 'to the heat resistin -property,

0 while the nickel adds greatly to t e strength and ductility. 'Further, the nickel and possibly the manganese and chromium all contribute to making it rust-resistant. The relatively high percentage of carbon avoids the necessity of using more manganese and a part of the carbon is held in solution by the molybdenum when the metal is in the molten state. The silicon offsets, to some extent, the brittleness contributed by the manganese.

Application filed Kay. 10,- 1929. -SeriaLNo. 362,147..

It has been found that this improved alloy steel has adequate-ductility to afford the necessary strength forbars and plates such as I are used in jails and vaults. It will withstand heavy blows and strains and bend .consider- :5

ably without breaking. -It cannot be easily 'filed, sawed or drilled with ordinary tools.

- Neither the hardness destroyed by the application of heat. Moreover, it is practically I rust-proof and will last almost indefinitely.

Thus, the material answers all of the necessali'y requirements for jail cells, vaults and the What is claimed is:

Y 1. A tool-resistant and heat-resistant alloy '05 steel of the character described containing 1.60 to 1.70% carbon, 6.50 to 7.50% manganese, 1.00 to 1.50% chromium, 1.90 to 2.50% nickel and 0.25 to 0.40% molybdenum.

2. An alloy steel having the properties described and. containing 1.60 to 1.70% carbon,

6.50 to 7.50% manganese, 0.60 to 0.70% silic0n, 1.00 to 1.50% chromium, 1:90 to 2.50% nickel and 0.25 to 0.40% molybdenum.

In testimony, that I claimthe foregoing as own, I have hereto aifixed m signature.

y DAVID FRANKLIN YOUN BLOOD. 

